The invention relates generally to the field of electronic photography, and in particular to digital photography systems that interface with a host computer.
Some digital cameras in the prior art, such as the Kodak Digital Science(trademark) Professional DCS 420c Digital Camera, manufactured and sold by Eastman Kodak Company, capture and digitize images from a single charge coupled device (CCD) image sensor and store the resultant digital data as relatively xe2x80x9crawxe2x80x9d (unprocessed) data in a non-volatile image memory, such as a PCMCIA-ATA type III removable hard drive. Such xe2x80x9crawxe2x80x9d data will typically contain one color value per pixel since the image is captured through an array of color filters. These xe2x80x9crawxe2x80x9d images are then transferred to a host computer, which in turn performs numerous image processing operations to render the images usable on an output device such as a monitor or printer. This process requires camera-specific image processing software to be available on the host computer in order to accomplish this image rendering. The image processing performed on the host computer typically includes steps such as interpolating the xe2x80x9crawxe2x80x9d color filter array image data into full RGB records (i.e., full color information for each pixel), color matrixing to improve the color reproduction, and tone scale correction to improve the tone scale rendition of the image.
Other cameras described in the prior art, such as the cameras described in U.S. Pat. Nos. 5,477,264; 5,016,107; and 5,528,293, implement similar image processing inside the camera (rather than in a host computer), so that the images stored in the non-volatile memory contain xe2x80x9cfinishedxe2x80x9d image data (rather than xe2x80x9crawxe2x80x9d data) in a standard file format, such as the JPEG interchange format described in ISO/IEC 10918-1:1994. (xe2x80x9cFinishedxe2x80x9d is herein used to mean that the data has been processed for camera-specific parameters (such as color filter array pattern, color and tone scale anomalies, edge quality, compression, etc.) and then converted into a standardized file format.) This allows the image files to be viewed and utilized by any software package that supports the standard file format, without requiring any camera-specific software on a host computer. Unfortunately, providing xe2x80x9cfinished filexe2x80x9d processing in the camera normally requires that the camera use expensive processing hardware, and/or relatively unsophisticated image processing algorithms, in order to minimize the processing time per picture.
If the processing time per picture is long, either the time the user must wait before taking the next picture will be equally long, or else an expensive, multi-image buffer memory must be provided, as described in the aforementioned U.S. Pat. Nos. 5,477,264 and 5,016,107, so that a new image can be taken while the previous image is being processed. What is needed is a digital camera architecture that enables the camera to provide xe2x80x9cfinished filesxe2x80x9d using sophisticated image processing algorithms, without requiring a multi-image buffer memory or expensive real-time image processing hardware, and without requiring the user to wait a long time for the image processing to be completed after each image is captured.
The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, an electronic still camera includes an image sensor for capturing an original image and generating image signals corresponding to the captured original image, an A/D converter for converting the image signals into original digital image data representative of the captured original image, an image processor for processing the original digital image data to generate processed image data, and a non-volatile memory for storing the processed image data, wherein the non-volatile memory also temporarily stores the original digital image data at least until the image processor completes image processing of the original digital image data.
In a further aspect of the invention, the image processor incrementally processes the original digital image data such that processed image data of each increment is stored in the non-volatile memory as each increment of processing is completed, while the non-volatile memory also temporarily stores the original digital image data until the incremental processing is completed. The incremental processing of the original image data can then be interrupted in order to capture a new image, while the processed image data for the completed increments of the original image is saved in the non-volatile memory.
The advantage of the invention is that the camera uses non-volatile transfer memory to store image files as they are incrementally processed, and interrupts this processing whenever the user decides to take a new image. The camera processes images only during the idle times, i.e. times the camera isn""t being used to capture an image. When the user wants to capture a new image, the camera xe2x80x9csuspendsxe2x80x9d the image processing operations on the previously captured xe2x80x9colderxe2x80x9d images, allows the user to capture xe2x80x9cnewxe2x80x9d images, then resumes image processing of the older images, followed by the newer image. This allows the time between captured images to be minimized, without using costly multi-image RAM buffers or high-speed processing hardware.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.